Northern Ireland's new Assembly Speaker has described his appointment as "hugely symbolic".

Mitchell McLaughlin, 69, a former Sinn Fein general secretary from the Bogside in Londonderry, has become the first republican to hold the office after securing cross community support during a vote at Stormont.

The South Antrim MLA said: "It is a new beginning that there is somebody from a broad nationalist/republican tradition in this position.

"Obviously Stormont has its own history and the various agreements since 1998 really have been addressing the process of re-balancing the dynamics between the different cultures here.

"I think it is certainly hugely symbolic and hopefully people see it as an important development. History is being made."

Two other candidates - the SDLP's John Dallat and Roy Beggs from the Ulster Unionist Party - were nominated, but with the two largest parties backing Mr McLaughlin, they failed to gain enough support.

Both the SDLP and UUP slammed what they described as a DUP/ Sinn Fein power-carve up, while some of the most scathing criticism came from the Traditional Unionist Voice leader who claimed MLAs should "hang their heads in shame" over the decision.

Mr McLaughlin said he would set aside party politics and offered assurance that his critics would be treated fairly if they stuck to the Assembly's rules.

"This is day one," he said. "I will be non party political. I will be rigorously impartial and they will know in terms of their experience in the chamber, providing they adopt the same rules and procedures as the Assembly has decreed.

"They won't run foul of me in terms of any personal animosities or criticisms or disappointments.

"As of today I have a new role and it won't be a Sinn Fein person defending the Sinn Fein position.

"It will be a Sinn Fein speaker who is impartial on all of the issues that the party might want to debate and agree or disagree on. My job is to ensure that we have a good, open and transparent process based on mutual respect and abiding by the rules that this Assembly has designed for itself to govern that business."

Mr McLaughlin takes over from the DUP's William Hay who stood down in October due to ill health.

The move comes after a deal, dating back to Ian Paisley's time, when it was agreed Sinn Fein could take on the role of Speaker, half-way through the current Assembly term.

The appointment was delayed, however, when the DUP refused to back him until a dispute over welfare reform resolved.

Mr Robinson told the Assembly he could now honour the agreement.

Pledging support, the First Minister said: "Let us remember this is a house that won't have a Speaker unless there is an agreement in particular amongst the two main parties (and) therefore would not operate and function properly without it.

"We indicated that we would honour the agreement to have a Sinn Fein nominee in that position when Sinn Fein had agreed on the issue of welfare reform. I am pleased to say and to see that has happened. I therefore intend to honour that agreement and give support to Mitchel McLaughlin."

Although Mr Robinson issued a warning that party political connections should be cut.

He added: "There should be no party instructions to a Speaker. The Speaker must act independently in that office and I trust that is what will happen."

Making the nomination, Deputy First Minister Martin McGuinness - who described himself as a long-time friend of the new Speaker - said his appointment would send out a strong message about inclusiveness.

He said: "Mitchell and I have been friends for 40 years. I know his ability, dedication and thoughtfulness of his approach to political life.

"I believe him to be well suited to fulfil the onerous responsibility of being Speaker of this Assembly.

"I believe that Mitchel McLaughlin will, as William did, win the respect and admiration of the whole house."

Mr Hay retired from the Assembly in October because of heart problems but acceded to the House of Lords and is expected to take his seat later this week.